Fuel-valve-operating mechanism



Patented May 1, 1928.

PATENTOFFICE.

LEONARD v. nosronn, or ron'rnmn, OREGON.

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Application filed January as, 1926. serial m. 84,422.

This invention relates generally to inter nal combustion engines, and particularly to a special form of valve lifting mechanism for Diesel engines.

The first object of this invention is to provide an exceedingly simple governing device for Diesel engines in which the amount of work performed bythe governor is reduced to the minimum.

The second object is to maintain a fixed relation between the governor speed and the height to which a fuel valve can be lifted.

The third object is to so simplify the construction of the governing control that its construction, assembly and takedown will be greatly facilitated.

The fourth object is to control the supply of'fuel to the cylinders close to the point of delivery instead of at the fuel pumps, as is usually the case.

The fifth object is to reduce the tendency toward racing when the load is suddenly removed from the engine. 1

These, and other objects, will become more apparent from the specification following as illustrated in the accompanying drawings, in which:

Figure 1 is a side elevation of the device with a portion broken away in section showing the parts in position for the maximum lift of the fuel valve but with the valve closed and showing its relation to a typical governor and also to a cam by which it is operated through a push rod. The cam housing in this view is broken away in section. Figure 2 is a horizontal section taken along the line 22 in Figure 1. Figure 3 is a vertical section taken along the line 3-3 in Figure 2 at an enlarged scale and showing the parts in the same relative position as in Figure 1 but with the plunger resting on the wedge or in the valve operating position and for a smaller lift of valve. Figure 4 is a modified form of the device similar to Figure 1 but showing the operating cam at the top of the engine instead of at a lower position, as shown in Figure 1..

Similar numbers of reference refer to the Referrin in detail to the drawings, there is indicate the top of an engine cylinder 10 on which is mounted the usual fuel valve 11. A governor 12 is indicated mounted on the housing 13, which includes the drive gears 14 and 15, the latter of which is mounted onthe'cam shaft 16 on which is mounted a fuel cam 17 t On the head 10 is secured a frame 18 by means of the bolts19. In the frame 18 is slidably placed the horizontal wedge 20 on one end of which is attached one of a pair of levers21 by means of the links 22, which levers act as a bell crank having a single upper end and as many lower ends as there are valves to be controlled. The connecting rod 23 joins the upper lever 21 to the lever 24 on the governor 12. l

In the frame 18 is slidably placed the vertical plunger 25 whose rounded end 26 is urged away from the top side 27 of the means of the pin 35 to the push rod 36 which terminates in the guide 37 for the tappet 38. The shaft 39 for the levers 21 transmit pin 34 and is joined at its opposite end by motion from the governor lever 24 through i the upper lever 21 to all of the lower levers 21 for the various cylinders.

The relation which the device bears to one cylinder only is shown, since it follows that the same action can be applied to any number of cylinders. I

In the modification shown in Figure 4 the cam shaft 40 is shown in an elevated position near the top of the engine, as is the case in some designs of Diesel engines. In this modification" the cam 41 engages the roller 42 on the arm 43 which is pivotally mounted on the standard 44 on the cylinder 6 head 10. A short link 45 connects the arm 43 to the lever 30. The remaining parts in Figure 4 are the same as in Figure 1.

The spring 46 is placed around the plungor 25 and its function is to sustain the weight of the parts resting on the plunger in a manner to hold the rounded point 26 off of the surface 27 whenever the lobe of the cam 17 is not raising the tappet.

The operation of the device is as follows: Assuming that the engine is in operation and the cam shaft 16 and governor 12 are functioning, it will be seen in Figure 1 that the governor 12 has no other work to do than to position the wedge 20 under the plunger which normally does not rest on the surface 27 of the wedge 20, but is urged away therefrom by the spring 46. However, in its rotation the cam 17 raises the tappet 38 and through the push rod 36 and lever 30 exerts an upward lift on the valve stem 29. Downward pressure on the lever 30 at the pin 34 causes the spring 46 to be slightly compressed and to allow the rounded end of the plunger 25 to rest on the surface 27 of the wedge 20. It follows that the spring 46-cannot be further compressed and that the remainder of the movement of the arm result in a lift of the valve stem 29.

In Figure 1 the engine is operating below the desired speed and the governor has moved the wedge 20 so that its highest point will engage the plunger 25 as early as possible, thereby resulting in a greater valve lift.

In Figure 3 the engine is operating above the desired speed and the governor has withdrawn the wedge 20 thereby reducing the amount of valve lift. Owing to the fact that the spring 46 is sufficient to support the weight of the plunger 25 and its end of the lever 30 it is evident that the only work which the governor must do while changing the position of the wedge 20 to correspond with the engine speed is to slide the wedge 20 within its guide. Any load which may rest upon the wedge from the plunger action is only momentary and occurs at the instant when the cam 17 is passing under the tappet 38.

It is a well known fact that it has long been the practice to employ governors for the purpose of controlling the operation of the fuel pumps themselves. this has its objection since it place a load on the governor making it less sensitive to slight changes in speed, owing to the greater range of speed required to produce the desired controlling action.

I am aware that many forms of valve operating mechanisms have been constructed in the past; I therefore do not claim such devices broadly, but I do intend to cover all adapted to lift said valve stem; means for rocking said lever; and wedge means interposed between said lever and its support whereby the lift of said stern can be varied by the engine governor, said wedge supporting said lever only during the period during which the valve is lifted.

2. A fuel valve operating mechanism having, in combination, a valve stem; a lever adapted to lift said stem, a slidable fulcrum for said lever; a wedge under said fulcrum; a spring supporting said fulcrum above said wedge and away from same; a governor; means whereby said governor can operate and move said wedge in a manner to engage and raise said fulcrum when the governor is decelerating and to lower said fulcrum when said governor is accelerating, said wedge engaging said fulcrum only when said valve is lifted.

3. A fuel valve operating mechanism having, in combination, a valve stem; a lever for raising said stem; a cam for rocking said lever; a fulcrum for said lever normally supported by a spring; a wedge under said fulcrum normally out of contact with said fulcrum; and a governor adapted to slidably move said wedge said fulcrum resting on said wedge only when said stem is being lifted.

4. A fuel valve operating mechanism having, in combination, a-fuel valve whose stem projects therefrom; a lever for lifting said stem; a cam for rocking said lever; a plunger acting as a fulcrum for said lever; a frame for supporting said plunger; a spring under said plunger urging same toward a raised position; a wedge slidably mounted in said frame under said plunger and normally not contacting therewith except at the moment a of lift of said stem; and a governor adapted to move the high point of said wedge under said plunger when said governor is decelerating and to mom a lower point under said plunger when accelerating.

LEONARD V. HOSFORP 

